This invention relates generally to the art of fluid sprinkling and more particularly to the manufacture of snow with elongated pipe-type snow making towers.
Numerous systems have been developed for artificially producing snow with tall or elongated pipe-type snow making towers which extend above ground anywhere from twelve to fifty plus feet. Two well known different techniques are employed for manufacturing snow with such towers. The first is an older technique wherein air and water under pressure are mixed together internally at the base of the pipe-type snow making tower and then the combination is ejected at the upper end of the tower into the ambient atmosphere in subfreezing conditions through snow making nozzles. This well known system is described in the present inventor's U.S. Pat. No. 3,706,414.
The advantage of such elongated pipe-type snow making towers is that the air line terminates at the tower base so that there is no exposed elongated air line to freeze, and due to the height of the tower, a long dwell time is obtained. Dwell time is the time between the time the seed crystals are formed upon discharge from the nozzles and the time the snow crystals, as formed from seed crystals, finally settle upon the underlying ground or ski slope.
One problem encountered with the snow making towers of the type disclosed in the inventor's U.S. Pat. No. 3,706,414, wherein the air and water under pressure are mixed at the base of the elongated pipe tower, is that obviously the internal water pressure can never exceed the air pressure. If this should occur, the water would back down the air supply line and prevent any air from entering into the mix.
Another disadvantage of this type of system is that the air pressure entering the lower end of the tower is not the same pressure as the air pressure or mixed fluid medium at the top of the tower which is ejected through the nozzles. In other words, a tremendous amount of energy is lost. For example, if the air compressor utilized to supply the tower has a capacity of 100 psi pressure, it would obviously be desirable to maintain this 100 pound pressure at the highest point of discharge on the tower.
Actual tests show, however, that the maximum effective air pressure discharge in such a tower at 35 feet above the ground is only approximately 85 pounds. Thus, with this type system one is faced with a 15 pound efficiency loss in air pressure, which of course greatly decreases the quality and quantity of snow being manufactured. In order to alleviate this problem, the present inventor conceived the snow making tower illustrated and described in U.S. Pat. No. 3,822,825 wherein the water and air under pressure are externally mixed at the top of the tower and the air line is insulated within the water line making up the pipe structure for the snow making tower to prevent freeze-up in the air line. To date, this method of external mixing of the air and water has proved to be the most efficient and is the most followed practice for elongated pipe-type snow making towers.
However, the present inventor has conceived a new apparatus and method whereby the advantages of both such prior art methods may be taken advantage of and utilized and whereby additionally the aforementioned problems with intermixing of air and water under pressure in snow making towers of the type disclosed in the inventor's U.S. Pat. No. 3,706,414 are effectively diminished.